Hand held bag-valve-mask resuscitators are used by trained first aid or medical personnel to supplement breathing when respiratory activity in a patient is impaired or absent. Pocket masks are also used to resuscitate patients. Pocket masks fit directly over a patient's face, covering the nose and mouth, and have a mouthpiece for an operator to breathe into. Such a device allows the operator to perform artificial ventilation on a patient and in some cases a supplemental oxygen feed line is applied to feed oxygen to the patient. The pocket mask is held in place with two hands, ensuring an effective seal. There is direct lung to lung transfer of air between the operator and patient and this transfer of air directly from the lungs of the operator to those of the patient provides an avenue of infection. Furthermore, the pocket mask provides a lower concentration of supplemental oxygen than is possible with a bag-valve-mask resuscitator because the exhaled air from the operator mixes with the supplemental oxygen.
Bag-valve-masks presently used today have a squeezable bladder connected to a face mask covering the nose and mouth of a patient. The bladder can have a supplemental oxygen feed line and also an oxygen reservoir. The bladder is squeezed by hand and this compression forces oxygen therein through the face mask into the lungs of a patient. Such a system does not permit the transfer of air directly from the lungs of an operator to those of a patient. The face mask has a purge valve therein which permits oxygen to be forced into the mouth/nose of a patient but does not permit air exhaled from a patient to pass through the face mask into the bladder. This exhaled air is vented through the purge valve to the atmosphere.
After being squeezed, the bladder is released and reforms allowing oxygen to refill the bladder from the oxygen reservoir and from the oxygen supply. If there is not sufficient oxygen present, then a flap valve is provided to permit air to be drawn into the bladder at the same time. All these types of resuscitators are provided with a pressure relief valve so that if the pressure from the oxygen supply should become too high, then it bleeds off into the atmosphere.
Properly used, bag-valve-mask resuscitators with supplement oxygen feed line and reservoir bag attached can move 800 millilitres or more of 100% oxygen into the patient during each compression cycle. The hand operation of the bag-valve-mask allows the operator to provide a wide range of frequencies of respiratory cycles according to the patient's needs and up to the point where the operator's hand tires.
For effective operation, however, the bag-valve-mask resuscitator requires two people to operate it, and the patient must be supine. An operator must maintain proper head and neck position to operate the bag-valve-mask and at the same time must also squeeze the bladder to supply oxygen to the patient's lungs. However, in order to maintain a seal of the face mask to the patient's face, two hands are nearly always required. Therefore, one operator is required to position and hold the face mask in place and at the same time maintain head and neck position of the patient, while the second operator is required to squeeze the bladder. Such a resuscitator is disclosed in U.S. Pat. No. 5,163,424 to Kohnke.
Another type of resuscitator is shown in U.S. Pat. No. 5,222,491 to Thomas which provides a bladder which may be collapsed by a mechanical mechanism.
Yet a further example of a resuscitative device is disclosed in U.S. Pat. No. 3,291,121 to Vizneau, wherein a bladder inside a bladder is provided. When the outside bladder is squeezed, oxygen in the bladder is forced into the mouth of a patient from the outside bladder through a first tube and at the same time the inside bladder is deflated, pushing air to the atmosphere. When the two bladders are released, the outside bladder fills up with oxygen or, indeed, may be filled up by being blown into by an operator. The inside bladder draws air exhaled from the patient along a second tube and is then expelled in the next squeezing cycle.
Another example of a resuscitator is shown in Canadian Patent No. 646,890, wherein a rigid container is provided having a flexible diaphragm therein sealed in the center. One side of the container is connected to a face mask and the other side of the container is connected to a mouthpiece for an operator to blow into. There is an oxygen supply for filling the side of the container to be expelled through the face mask into the lungs of a patient and when an operator blows through the mouthpiece, the diaphragm moves in the container forcing oxygen therein through the face mask into the patient's lungs. When the container is empty, then it is necessary to allow more oxygen to enter the container and the diaphragm moves back towards the operator's side. The system may work well, but can only work by blowing and does not have the ability of being able to be squeezed as no bladder is provided. The container is a rigid container.